Traffic signal



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4BY ATTORNEY L. SWAM TRAFFI C S IGNAL Filed Oct. 10, 1929 June 24, 1930.

Patented June 24, 1930 UNITED vsTA'rEs PATENT OFFICE Lors swm, or sT. LOUIS, MrssoUnr TRAFFIC SIGNAL Application led October 10, 1929. Serial No: 398,688.

the use of this type of signal difliculties arise,

due to the'failure to indicate the interval of time that a given light has continued its signalling function, and it is diiicult, if not impossible, to determine whether or not it will be safe to enteran intersection while the travel signall light remains lighted ifl that light has been on ydisplay for any considerable interval before the ,-,attempt is made. This fault is particularly embarassing to pedestrians, who often enter an intersection on a clear'signal only to have that signal change when they have but partially' traversed the intersection, with the result that they are left unprotectedjn the changing trailic stream. f

The invention primarily has for its o'bject, therefore, the lprovision of a novel means for indicating to pedestrians and vehicular traic the intervals of time during which-it may be expected to remain on display, .so that a person onfootor vdriving sonable certainty of his ability to completely traverse the intersection before the next traiiic change.

In its more resides in the provision of a light having a time interval representing the timeallotted to pedestrians and vehicular traiiie to effect the crossing of an intersection in a given direction, and mechanical means effective during that interval to gradually block `out that light, the continually increasing blocked-out part representing the portion of the time interval that has'been spent, and the unblocked .part representing the portion of the interval remaining and during which a crossing may still be attempted. Means is also provided for indicating that point` a which it becomes -unsafe to further atw tempt crossings on 4foot or in vehicles.

ment of the shutter.

a vehicle may enter an intersection with readetailed. nature. the invention With these and other objects in view which will more fully appear, the nature of the invention will be more clearly understood by following the description, the appended claims, and the several views illustrated in the accompanying drawings.

In the drawings:

Figure l is a face view illustrating a signal embodying the invention,

Figure 2 is a. rear view,

Figure 3 is a central vertical cross section,

.Figure 4 isa horizontal section taken on the line 4 4 of Figure 1, and Figure 5 is a perspective view of a frag- Like reference numerals designate corre-vr` sponding parts throughout the several figures ofthe drawings:

In the drawings, 1 designates a standard upon which the signal head may be'supported for suitable display. The head comprises a box-like casing 2 constructed to provide a central hollow column 3 which is flanked by red and green signal compartments 4 and 5 respectively, the latter hous- 75` j ing the propersifgnal lamps 6 and 7. The

casing 1s equippe with windows 8 through @which the lights 6 and 7 may be displayed,

and these lights may be lighted and timecontrolled in the usual manner. The specie means for controlling the green and red signals form no part of my present invention and no further disclosure of these features need be made herein.

The interior of the column 3, may be viewed' through a `glass covered window -9, and a plurality of lights 104 `(two being shown) are positioned in the lcolumn and are adapted to be lighted during each intervalof green light display for a reason that will soon'be explained. The number and color of the lights 10 is immaterial,A in fact the now popularneon tube might be employed with facility. A reector wall 11 is positioned behind the lights 10, so thatA 95 their effect is augmented by theresulting reflection. A. spool or drum12 is rotatably mounted in each of the upper and lower -ends ofthe column 3 and said spools serve to mount an ",100

- the whole light column will have been closedV endless shutter or light blocking device. Rotation may be imparted to one of the spools 12 byl suitable power transmitting connections 13 from a reversible motor 14. The

motor is connected in a suitable power circuit diagrammatically indicated at 15, and a suitable reversing switch may be employed for effecting a reversing of the direction of rotation of the motor at regular intervals. The switch may be of any suitable construction and is diagrammatically indicated at 16.

An endless belt or apron takes over the spools 12 and comprises a pair of spaced flexible wires or cables 17, the front Hight passing in front of the reHector 1l and the rear Hight passing to the rear thereof so as to be out of view. A plurality of thin opaque plates 18 are secured upon the wires and collectively provide a flexible shutter capable of being presented in front of the lights 10 to shut olf the llght emitted by them from the column 3.

A pair of contact members 19 maybe carried by the wires 17 in suitable spaced relation so that one thereof will act to trip the motor reversing switch each time the shutter reaches an extreme position.

In operation, assuming the red light of the trafhc signal to be lighted and its interval of lighted condition just about spent, the green light will be about to be lighted and the shutter will have about reached lts fully retracted position with one of the contact members 19 about to actuate the motor reversing switch.

As the red light is extinguished and the green light brought into function, the contact 19 above mentioned actuates the reversing switch and reverses the motor 14 causing the shutter 17, 18 to start travel in the reverse,y direction.

It yshould be understood that the lights 10 are timed with the green light 7 to be lighted and extinguished over the same periods. As the opaque plates 18 pass downwardly, one by one, past the lights 10, they shut ofi the column of light emitted through the front window bit by bit. The lowermost plate will reach the bottom just as the next light change is about to take place, at which time off by the shutter plates.

Concurrently with the light change from green to red, the other contact member 19 will actuate the reversing switch to reverse the motor and cause the shutter to return to the starting point above mentioned while the red light is in function, the operation above described being caused to repeat itself as the next succeeding light change takes place. l

Thus a person can, by watching the progress of the shutter plates 18 in obliterating the light column, readily observe how much longer the green light may be expected to remain lighted, and whether or not a safe ings may be safely attempted by pedestrians and vehicles respectively.

It is of course to be understood that the details of structure and arrangements of parts may be variously changed and modified without departing from the spirit and scope of my invention.

I claim: c f A 1. In a traffic signal, the combination of a clear travel signal operative at intermittent predetermined intervals, a signal light operative during the same intervals, aAmechanical shutter, means to actuate f the shutter to obliterate the light through gradual stages during each operative interval, and means to indicate the passage of a safety stage in the course of the light obliteration.

2. In a tratlic signal, the combination of a clearrtravel signal yoperative at intermittent periods of predetermined length, a signal light column operative at intervals coincident with the travel signal intervals, an opaque shutter, and means to move the shutter in front of the light column to gradually block out the light emitted therefrom, said shutter comprising spaced wire bands and opaque plates carried thereby.

3. In a traffic signal wherein is provided,`

a clear travel signal, a columnar casing having a window therein for emitting light, a light source in the casing, said clear travel signal and said light source being active at intermittent coincident intervals, a mechanif' cal shutter, means to move the shutter to gradually close 0H said window, said moving means being timed to cause the closing off function to begin and end coincidentally with the beginning and ending of said intermittent coincident intervals, and a reHector wall behind said light source, said shutter ycomprising an endless apron having opaque plates attached thereto yand having one Hight disposed to travel between the lightsource 'and the window while the other Hight travels gradually closefoff said window, and a reflector wall behind saidY light source, said shutter comprising an endless apron having opaque plates attached thereto and having one Hight disposed to travel between the light source and the window while the other light travels behind the reflector wall, said moving means comprising a pair of mounting spools, a reversible motor connected to impart rotation to one of the spools, and means carried by the shutter to effect reversal of the motor at the commencement and conclusion of each coincident intermittent interval.

5. In a traffic signal, .a columnar light source, a movable shutter disposedin two iiights arranged at opposite sides of the light source, and means to move the shutter flights in reverse directions.

6., In-a traiiic signal, a' columnar light source, an endless flexible movable shutter disposed in two flights arranged at opposite sides of the light source, and means to move the shutter.

7. In' a traffic signal, the combination of a clear travel signal operative at intermittent periods of predetermined length, a signal light column operative at intervals coincident with the travel signal intervals, an opaque shutter, and means to move the shutter in front of the light column to gradually block out the light emitted therefrom, said shutter comprising spaced wire bands and opaque plates carried thereby and being disposed in two reversely travelling flights one 3o before and one behind the light column. 8. lIn a traiiic signal wherein is provided a clear travel signal, a columnar casing having a window therein'for emitting light, a light source in the casing, said clear travel signal and said light source being active at intermittent coincident intervals, a mechanical y shutter, means to move ythe shutter to gradu- I ally close off said window, said moving means being timed to cause the closing off function 40 to begin and end coincidentally with the beginning and ending of said intermittent coincident intervals, and a reflector wall behind said light source, said shutter comprising an endless apron having an opaque portion and arranged in two vertical reversely travelling flights, one of which passes in front of the light source and the other behind the reflector Wall.

In testimony whereof-I aiix my signature. 5o LOIS SWAM. 

